Blind Image Watermarking Based on Adaptive Data Spreading in n-Level DWT Subbands

Abstract

This paper proposes a new adaptive watermarking scheme for digital images, which has the properties of blind extraction, invisibility, and robustness against attacks. The typical scheme for invisibility and robustness consisted of two main techniques: finding local positions to be watermarked and mixing or embedding the watermark into the pixels of the locations. In finding the location, however, our scheme uses a global space such that the multiple watermarking data is spread out over all four lowest-frequency subbands, resulting from n-level Mallat-tree 2D (dimensional) DWT, where n depends on the amount of watermarking data and the resolution of the host image, without any further process to find the watermarking locations. To embed the watermark data into the subband coefficients, weighting factors are used according to the type and energy of each subband to adjust the strength of the watermark, so we call this an adaptive scheme. To examine the ability of the proposed scheme, images with various resolutions are tested for various attacks, both pixel-value changing attacks and geometric attacks. With experimental results and comparison to the existing works we show that the proposed scheme has better performance than the previous works, except those which specialize in certain types of attacks.

Design of optimal blind watermarking technique based on MOEA/D

“…Also, we rotated watermark images by 10° in a clockwise direction for rotation attack, applied JPEG compression with QF from 30 to 90%. Under these attacks, we extracted watermark and calculated NCC values, then compared the mean value of nine images to other existing schemes in [10,11,12,19]. The simulation results show that the proposed method outperforms than other latest schemes for cropping and JPEG compression attacks.…”

“…As transform domain watermarking provides higher robustness than spatial domain watermarking, researches on robust watermarking methods in recent years have been mainly conducted in that direction. In particular, DWT, DCT and SVD have been widely used in watermarking embedding processes, and chaos and fractal theories have been introduced to increase the security of watermarking [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19].…”

“…For robustness evaluation, we apply several different attacks such as image processing, geometric transformation, and image compression, which were applied for robustness evaluation in existing schemes [5,10,11,12,17,19].…”

“…Also, NCC values of our method and other existing schemes under different attacks for robustness evaluation are listed in Tables 3 and 4. Table 3 shows comparison results between ours and other methods in [5,10,11,12,17] under image filtering, enhancement and noise attacks. As seen in Table 3, NCC values of our method for some attacks are highest, but values for some attacks are lower a bit.…”

“…As seen in Table 3, NCC values of our method for some attacks are highest, but values for some attacks are lower a bit. Lee et al [12] proposed watermarking scheme that used all four of lowest frequency sub-bands so that it could give high robustness than other's methods for image filtering and noise attacks such as median filter and salt and pepper noise. Ernawarn and Kabir [11] also provided empirical optimal parameter based blind watermarking method so it gave a good performance for image enhancement attacks such as image sharpening and histogram equalisation.…”